The present invention relates to couplers, and more particularly to couplers for securing a trailer to a hitchball attached to a vehicle. A standard coupler may be modified to provide the locking system of the present invention which ensures that when coupled to the hitchball the modified coupler will not be released, and when uncoupled from the hitchball, the hitchball receiving cavity may be locked closed thereby preventing unauthorized recoupling to a hitchball.
Existing couplers are normally provided with a separate cylindrical retaining pin which is insertable into a side hole rearward of the sleeve collar to prevent the rearward movement of the collar when the coupler is in the closed position. However, there is no means for positively locking the collar in the forward closed position to prevent the unauthorized insertion or removal of a hitchball. Further, the retaining pin is easily lost from the side hole.
Existing trailer hitches are shown in U.S. Pat. Nos. 3,797,283; 4,459,832; 4,776,607; 4,925,205; 5,154,440; and 5,222,755. However, nothing in the art teaches positively and directly securing the lever linkage in a closed, locked position. As will be described below, the present invention allows the coupler to be locked in a closed position to prevent the unauthorized insertion of a hitchball in an attempt to steal the trailer to which the coupler is mounted.